【芝士整理】CSS经典布局

水平居中

行内元素

text-align

.parent {
    text-align: center;
}

定宽块元素

常规流中

margin: 0 auto;

.child {
    width: 200px;
    margin: 0 auto;
}

浮动块元素

relative + 负边距

.child {
    width: 200px;
    float: left;
    position: relative;
    left: 50%;
    margin-left: -100px;
}

绝对定位元素

负边距居中

.parent {
    position: relative;
}
.child {
    width: 200px;
    position: absolute;
    left: 50%;
    margin-left: -100px;
}

绝对居中

.parent {
    position: relative;
}
.child {
    width: 200px;
    position: absolute;
    left: 0;
    right: 0;
    margin: 0 auto;
}

不定宽块元素

inline-block + text-align

.parent{
    text-align: center;
}
.child{
    display: inline-block;
}

transform

.parent {
    position: relative;
    height: 300px;
}
.child {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

flexbox

.parent {
    display: flex;
    flex-direction: row;
    justify-content: center;
}

table + margin:auto

.parent {
    display: table;
      margin: 0 auto;
}

table-cell + text-align

.table {
  display: table;
  width: 100%;
}
.table-cell {
  display: table-cell;
  text-align: center;
}

PS: 完整Demo - https://codepen.io/curlywater...

垂直居中

单行

line-height和height一致

.child {
    height: 100px;
    line-height: 100px;
}

定高块元素

负边距居中

.parent {
    position: relative;
}
.child {
    width: 200px;
    position: absolute;
    top: 50%;
    margin-top: -100px;
}

绝对居中

.parent {
    position: relative;
}
.child {
    width: 200px;
    position: absolute;
    top: 0;
    bottom: 0;
    margin: auto;
}

不定高块元素

transform

.parent {
    position: relative;
    height: 300px;
}
.child {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
}

flex

.parent {
    display: flex;
    align-items: center;
    height: 300px;
}

table-cell + vertical-align

.parent {
    display: table-cell;
      vertical-align: middle;
      height: 300px;
}

PS: 完整Demo - https://codepen.io/curlywater...

水平垂直居中

行内元素

text-align: center + line-height一致 + vertical-align: middle （近似居中）

.parent {
    text-align: center;
    line-height: 300px;
    height: 300px;
    text-align: center;
}
.child {
    vertical-align: middle;
}

定高定宽块元素

负边距居中

.parent {
    position: relative;
}
.child {
    width: 200px;
    height: 200px;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-left: -100px;
    margin-top: -100px;
}

绝对居中定位

.parent {
    position: relative;
}
.child {
    width: 200px;
    height: 200px;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    margin: auto;
}

不定块元素

transform

.parent {
    position: relative;
}
.child {
    position: absolute;
    top: 50%;
    bottom: 50%;
    transform: translate(-50%, -50%);
}

flex

.parent {
    display: flex;
    justify-content: center;
    align-items: center;
}

table-cell + text-align + vertical-align

.parent {
    display: table-cell;
    text-align: center;
    vertical-align: middle;
}
.child {
    display: inline-block;
}

PS: 完整Demo - https://codepen.io/curlywater...

上下布局

calc()

.header {
    height: 200px;
}
.content {
    height: calc(100% - 200px);
}

content absolute

.header {
    height: 200px;
}
.content {
    position: absolute;
    width: 100%;
    top: 200px;
    bottom: 0;
}

header absolute

.content {
    height: 100%;
    padding-top: 100px;
    box-sizing: border-box;
}
.header {
    position: absolute;
    height: 100px;
    width: 100%;
}

flex

.container {
    display: flex;
    flex-direction: column;
}
.content {
    flex: 1;
}

table(table-row里需要有内容)

.container {
    display: table;
}
.header, .content {
    display: table-row;
}

PS: 完整Demo - https://codepen.io/curlywater...

左右布局

float + margin

.left {
    width: 200px;
    float: left;
}
.right {
    margin-left: -200px;
}

float + BFC（左右两边都可自适应）

.left {
    float: left;
}
.right {
    overflow: auto;
}

PS: 完整Demo - https://codepen.io/curlywater...

左中右布局

left + right + margin（注意DOM节点顺序）

.left {
    float: left;
    width: 100px;
}
.right {
    float: right;
    width: 200px;
}c
.main {
    margin-left: 100px;
    margin-right: 200px;
    height: 100%;
}

float + BFC

.left {
    float: left;
     width: 100px;
}
.right {
    float: right;
    width: 200px;
}
.main {
    overflow: auto;
    height: 100%;
}

圣杯

https://codepen.io/curlywater...

双飞翼

https://codepen.io/curlywater...

flex

.container {
    display: flex;
}
.main {
    flex: 1;
}

table

.container{
    display: table; 
    width: 100%;
    table-layout: fixed;
}
.left,.main,.right{
    display: table-cell;
}
.main {
    width: 100%;
}

https://codepen.io/curlywater...

等高

padding + margin

.container {
  overflow: hidden;
  .left,
  .right {
    padding-bottom: 9999px;
    margin-bottom: -9999px;
  }
  .left {
    float: left;
    width: 300px;
    background: #333;
    color: #fff;
  }
  .right {
    overflow: hidden;
  }
}

border

.container {
  border-left: 300px solid #333;
  .left {
    float: left;
    margin-left: -300px;
    color: #fff;
  }
  .right {
    height: 100%;
  }
}

table

.container {
  display: table;
  width: 100%;
  .left, .right {
    display: table-cell;
  }
  .left {
    width: 300px;
    background: #333;
    color: #fff;
  }
}

flex

.container {
  display: flex;
  .left {
    width: 300px;
    background: #333;
    color: #fff;
  }
}

https://codepen.io/curlywater...

等分

百分比

.container {
    margin-left: -20px;
    font-size: 0;
}
.item {
    width: 25%;
    padding-left: 20px;
    display: inline-block;
    box-sizing: border-box;
}

flex

.container {
    display: flex;
}
.item {
    flex: 1;
}
.item + .item {
    margin-left: 20px;
}